Airplane-landing speed-retarding device



June 24, 1930. o. ALVISTUR AIRPLANE LANDING SPEED RETARDING DEVJECE Filed Oct. 10, 1928 2 Sheets-Sheet 1 INVENTOR. 0a a? l//6'77/ I B'Y 1 v ATTORNEY June 24, 1930. o. ALVISTUR 1,765,818

AIRPLANE LANDING SPEED RETARDING DEVICE Filed Oct. 10, 1928 V 2 Sheets-Sheet 2 INVENTOR. 0507/ A 1 V/577/E ATTORNEY Patented June 24,1930

I vosoi n nnvis'run} on OAKLAND; oALiFoania V iInrLAnnLAiinIuesrnnmnn'rnnnine nnvron The invention-forming the subject matter of this application'relates to devices for retarding thelanding speed of airplanes, and particularly to] collapsible propellers movable'in anactive position. to resist the flight ofthe airplane before landing.

The landing speed of airplanes is usually extremely high wh'ich renders the landingboth uncertain and dangerous, both to bystanders onthe field andto the occupants of the airplane.

'1he*priinary object "of invention isf the provision of a device which resists'the advancement of the airplane, said device being actuated. by the air current flowing past the airplane'in lii'ght,and said device, being adapted tobe held inan inoperative position duringthe-{normal flight of the airplane.

iii- I Another obj octof the invention is the pro: vision of collapsible propellers disposed in coacting relation to the wings of an airplane and adapted to 'beopened at will, so as to be driven by the 'air currentsproduced by the tractorpropeller of the=airplane; said collapsible propellers being so designed as to offer resistance to the passage of said a'ir'currents, thereby creating a 'baclcpressure and effectively reducing the speed of the airplane before landing.-

' A still further objectof theinvention is the provision of collapsible propellers of the pusher type to be used incombination I nected to landing lights, conveniently posi-" tioned on the 'airplane,' so that in the event I of night landing, the pilot,- by turning a switch,' may connect the current generated by saidgenerators to the landing l1ght s, 7 whereby landing of the airplane at night s greatly facilitated.

halves Gther objects of the invention areto pro-" I i vide a device of thexcharactei"described that Willb'e superior in point of si1nplicity,in-

,expensiv'eness of construction,' positiveness of operation, facility and convenience in use, and general efficiency.

In" this sp cification and the annexed draw ngs, the invention is illustrated in the form*considered'tobe the best, but it is to be understood that theinvention'isnot limited to such form because it may be'einbodied in otherforms. It is also to be 1111114 V derstood that in andjby the claims following: i

inventionin' whatsoever form it be'enr; bodied. [The invention 'is'clearly illustrated in the accompanying drawings, in which 'thej description, i't is desired to cover the "Figure 1 is' a plan. view of a biplane and the" tail of the fuselage, part of theupper l Wings being broken away;

v Figure 2 is afront-elevation of the'biplane, showing the retarding propellers in.

their open position Figuref3' is a fragmentary" side view of V l V the biplane, showing theari'angement of the means for holding theretarding propellers in place; and showing the'control for" releasing said holdingmeans, this figure also illustrating the mounting of the generator upon the retarding propeller; 1v i Figure 4 is a front-view of a collapsible propeller;

Figure 5 is a fragmentary sectional View of the spring latches for holding the oppositeTha'lves-of the collapsibleu'propellers in" a folded or collapsed position"; and

Figurefi is a top plan View of the collaps- 'ible p ropellerin a collapsed position, show-' ing its relative POSltl'OIilIl connection with I the generator onwhichtitis mounted, and

with the means for holding the opposite tion. r

Referring to the accompanying drawings, wherein similar reference characters desig nate similar parts tli'ruout, the various fig ures described above adequately illustrate my invention vand the following detailed description is commensurate with the above,

jofth e propeller in the collapsed pojsi c mentioned.drawings, in enabling an artisan to construct and assemble the constituent I 1 parts of the same.

' In carrying out my lnvention, I make use of an airplane having a fuselage 6, upper wings 7, lower wlngs 8, a tractor pros lpeller '9, and a landing gear thereon. It I isto be understood that although in the herein described embodiment of my" invention, I illustrate the device in connection with a biplane, my'device niayfbe mounted and function eiiiciently on monoplanes or othertypes of airplanes. Y

r In the biplane shown,

-the upperw1ngs 7 and the lower :wlngs S are connectedbymeans ofstruts 12. Ad jacent to each outerend of the lower wings between wo djacent struts 12,;18

mounted my speed retarding mechanism, denoted in 1ts entirety by the numeral 13,

which comprlses crossmembers 1 extending between and secured toithe adjacent "struts 12, a generator 16 1nounted on .Sitld cross members 14: substantially at the cross ing point thereofi and 7 av propeller, designated in its entirety by the numeral 17, and being mounted directly "on the rotor ofthe generator 16. Thekpropeller 17 is preferably of-the pusher type relativelyto the directionofIflight of the airplane,-and it has four. blades 18 thereon.

;oppo'site hub portions 19 carries two of means'of suitable hinges 22. f'The blades 18' and the hubs 19 are sodisposed that the blades .18.on each side" of the propeller, the hub portions 19' being" swingably secured upon a central hub, portion 21 by when the hubs '19 are turned around the hinges'22, sons to bring the blades 18 into #pmuensm with each other,the blades assume a parallel and spaced position rela'-.

tive. to each other, and the hub portions and 'the blades on theopposite sidesf'of the central portion, 21 are symmetrical.

Around each setof blades '18 1s a substantiallysemi-circular rim 23, each ofsaid rims 23 forming half of a ring so that when When not in operation, the propellers are held in afolded position and arefolded forwardly or toward the direction-of flight of the airplane, asshown in. the dottedline the propellers are open, the semi-circular runs '23 extend in continuation of each.

other and form a balanced ring around said propellers.

position in Figure 3. In this position, the

semi-circular rims 23 are also disposed in symmetrical position.

The propellers are held in the collapsed ori'foldedposition by means of spring catches 26, a'spring catch being disposed on each s de of the 001-" lapsed propeller so as to prevent the movingapart of the rims 23. In order to acc'omplisli this eifect, the catches engage the 7 outside face ofeach rim' when the rims are 'n the illustration,

Each of the folded. The" spring on a bracket 27,

Each spring catch comprises a 'cylinder 28 having a plunger 29 extending 'therethru',

said. plunger '29 being provided jwith an catches are supported enlargedhead 31. The cylinder 28is provided-with aperturesinthe o )po site...-encls" thereof so as'to allow the reciprocating move, 5

ment of the plunger therethru.

the direction of the propellen 17. The

smaller end of each plunger29 extends "into across headed Inorder-to preventithc sliding of the plunger 29 out of the. cross head 38 and also to. allow the employment of the cross "head 33 for pulling 'the 1 8 plunger 29 against the action of the spring 32, nuts are provided at the smaller 'end of the plunger 29, threaded' thereon,and bearing against theoutside face of the cross head p The plungers are operated by means of; 'the cross head 33, and the cross head is moved manually against the action of the spring 32, said movement being transmitted a i V to the cross head 33 by means of-a .lineiifi'm v connecting each plunger to 'a control stick;

37. Said line 36 ispreferably of the usual c'ableand is properly guidedon the airplane wings by means'of pulleys 38.

' r In operation, during the normal flight I the airplane, the retarding propellers 17 are folded'around the respective hinges 7'22 and are held in the folded position against. moving apart by means of the spring catches 26. Before landing, it is desired to reduce the landing speed and offer further resistance to the flight orso'aring thru the air;-

Therefore, the pil'ot'pulls the control stickB'Z toward the tail end of the fuselage,iwhereby a pull is exerted upon the line 36, moving the cross head away from the cylinders 28.,

which. in turn causes the movement; of the plungers 29 and 31 into the cylinder against the action of the spring 32. After theplunger heads 31 are withdrawn so-as not to obstruct the rims 23, then theaction of the wind or air currents created by the tractor propeller 9 will. force the opposite sections of the retarding propellers 17. apart around their hinges 22 until the same reach-the fully extended position in which they are held by the air pressure exerted thereon. I .7 l

V .In order'to assure the opening Oftheo-pposite half of the retarding propellers18,

Iuse a compression spring 39, one end of which is secured to one of the hubs 19,.a-nd said compression spring 39 1s disposedin such a manner as to bear against the other hub 19 when the propeller isin thefolded position. released, the action of the compression Thus, when :the catches 26 .are r spring 89 tendsto inovethe hubs 19 apart from each other, thereby assuring the turhing of the propellers sufiiciently far to be the open position in the manner heretofore described; I I v *L-The propeller blades 18are'designed at a such an angle as to form pusher propellers,

' byv vwhich landing lights are 'illui'ninated.

and they are so disposed that the indraft of these, propellers tends to 'occur from the direction of the tail of the lane.- There,

fore, they ofler effective res stance to the passage of the air currents created by the tractor propeller 9 andsuccessfully resist the flight oi':' the airplane. The action of the air currents on the propeller blades 18 will result in the rotation of thewhole propeller Y mechanism 17, and inasmuch as there is a tendency of indraft from the direction of the tail end of the airplane, the pusher 'propeller eificiently creates a pressure counteracting partof the air pressure created by the tractor propeller 9', whereby the landing speed of the airplane is .materially'reduced and rendered safe. After the airplane is on the landing field, then the-opposite halves of the collapsing propellers 17 are collapsed or folded in the position heretofore described During the turn ing of the opposite halves of the propellers 17 in the folded position, the stick 37 is and held in that position.

moved again in a catch Withdrawing position.

\Vhilc the propellers 17 are rotated by the air, currents, there is electric current created in the generators v16 in the usual'manner. lVhile the terminals of the generators may be connected to the radio set or to any other device in the airplane where electricity may be utilized, I'prefer to use the electricity thus generated for the purpose of lighting the landing lights. Such landing lights are designed by the numeral 41' and are disposed on the lower face'of the lower wings 8, adjacent to the opposite 'ends thereof. I

propose to use a switch connected in series between thelanding lights 41 and the generator 16 by which the landing lights 41 may be turned on at night, at will.

It will be recognized that a partlcnlarly simple and efficient device is provided tor efliciently reducing the landing speed of airplaiies. The device is readilycontrolled by the pilot thru the conventional. control means, means being provided for securely holding the device into inoperative position'. The device is actually opened n the operative position thereof by the action of the air currents and is so designed as to counteract the action of the tractor propeller/9Q The rotation of the retardingpropellers is utilized for generating electricity,

The controlling of the device is simple, and

glefmovement of the control sticln :1 'lainizh: 7 I, v a

l 1. A landing-r speed v reducing device gfior, airplanes, comprised ,of collapsible-rpusher' propellers, rotatablv 'mounted one the airplane at, each'sideof the fuselagethereof; means "for holding'said propellers in a cola lasedji aosition' and releasineh'means."for

said holdingineansysaid propellers"being: i

adapted be i nfolded and maintained "in an operative. position and i'otat-edb-ythe win d'pressurethereon. i I 2, A land ng' speed reducing vdevice for airplanes comprising a pusherprop'ellerio;

tatably mounted on the airpla i1e, a hubf'of the propeller being made in three'sections,

theside -sections being tnrn'able' in a parallel position around the central section'tblad'es symmetrically arrai'igedjon the side sections so as to be'turnable in the direction'offliglit; into inoperative plositionjm eans for holding said bla'def'sin inoperative position; meaiis-i" r on said'jprop'ellers for engagementwith said;

holding means when the blades are turned in the directionoffiight; and means "for releasingjatfwill said holding means"; said bladjesjbeings o arranged as to be turned away from each other and rotated by the ing a central hub section; side hub sections on the opposite sides thereof, being turnable toward and away from each other; propeller blades are radially disposed relative to the" central hub S6Ct1OI1;-II1G&I1S for engaging said rings in the inoperative position of the blades for maintaining the mechanism inaction of air currents created by thefiight.

3. A speed retard ng mechanism comprisoperative; and means for releasing said engaging means at will; said propeller blades being so arranged as to be turned'apart from each other and rotated by the thrust of ind currents thereon.

j 4. In an airplane, a plurality of speed re tarding mechanisms mounted in balanced position upon the Wings of the airplane;

each mechanism comprising a propeller;

blades on the propeller turnable in a substa-n tiall J parallel position with each'other;

ring sections secured to the outside edge of I the propeller blades so as to form'a circular ring around the propeller when in operative position; means for engaging said ring sec j @lO11S,'XVl1G11 l l1(- propell r blades are in inop- I erative position; and means releasing said engaging means at will; said propellers being so arranged as'to" be moved away from each other and rotated by the action of air enrrents' thereon T 1 V v 5. In an airplane, a 'plnr alityof speed re- 7 I ,f tard'ing mechanismsmounted in balanced a 53 position "upon thewings of the airplane; a each speed retarding Ineohanismeomprising V j a propeller hub mounted onthe Wing and v beingfrotatable in plane at anfangle to'the eupporting surface of-the' airplane {hnbfsections on the opposite sides'of the hnb turna able aroundthe central portion of the hub in the. dire'otionofrflight; apropeller blade I on each turnable' h'ub sectio-n; a. half; ring t secured to the outsideedge of the propeller; the half ringson the oppositelsides of the mechanism describing a Circular rim when the opposite propellers are positioned in the same plane; means engaging the outside J faces of, the half-rings when the same are a 20 :tu'rnedin a substantially. parallel relation or holding the propellers in inoperative po: sition (edgewise'to the direction or" flight) Vmean s to releaeesaid engaging means at t Will, thereby allowing the Wind pressure 5 to move the propellers j'apart and turn the same-in operative position and to rotate the sa me and a generator connected to landing "lights of'the airplane, and beingdriven by p said retarding ineohanism. v In testimony whereof I afiix my signature.

OSCAR ALVISTUR. 

